Citral is a major constituent of Cymbopogon citratus or lemongrass oil. The anti-clastogenic effect of citral (20 mg/kg) was tested against the known mutagens cyclophoshamide, mitomycin-C and nickel metal (NiCl2) in mice. Micronucleus (MN) frequency was evaluated in both bone marrow and peripheral blood erythrocytes. The sampling was done after 24 h, 48 h and 72 h of clastogen treatment. Results show that citral had significantly (p < 0.01) decreased the frequency of MN induced by the three clastogens in bone marrow and peripheral blood erythrocytes.